1. Technical Field
This invention relates to the field of fiber-optics, and more particularly, to an improved optical backplane.
2. Description of the Related Art
An optical backplane is a structure having a variety of connectors facilitating the interconnection and communication of different systems and components. More specifically, the optical backplane is configured for the interconnection of systems and components having high bandwidth optical interfaces. Conventional optical backplanes, however, also can include electrical connections and suitable interface circuitry for interconnecting systems and components having electrical interfaces. Though optical backplanes can be used within a variety of settings, optical backplanes are often used to interconnect control systems within aircraft. In consequence, optical backplanes must conform to strict size limitations and facilitate the replacement of components with a minimum of downtime.
Conventionally, optical backplanes have been configured according to one of two differing design methodologies. The first design methodology utilizes a series of individual fiber-optic fabric inter-connectors (fabric inter-connectors) for connecting individual pairs of optical backplane connectors. Despite any advantages afforded by this design, this xe2x80x9cpatch cordxe2x80x9d approach can yield a complicated and disorganized conglomeration of fabric inter-connectors. Often, the individual fabric inter-connectors are similar in appearance, if not indistinguishable, from one another making service difficult. Should a fault occur, the individual fabric inter-connectors corresponding to a given system or component must be identified, traced to their respective termination points, and checked to determine which fabric inter-connector is responsible for the faulty connection. Serviceability of the optical backplane becomes even more problematic with regard to xe2x80x9cin fieldxe2x80x9d repairs where conditions are typically less than ideal.
The second design methodology seeks to inter-connect all optical backplane connectors using a single, primary fabric inter-connector wherein individual branches with connectors extend off of the main portion. Under this design methodology, the optical fabrics are manufactured as a single inter-connector in either a long fishbone or a serpentine design. The serpentine fabric inter-connector essentially loops throughout the optical backplane in a serpentine or snake-like fashion in an effort to pass in close proximity to many of the optical backplane connectors. The serpentine fabric inter-connector links to the individual optical backplane connectors via small branches extending from the primary serpentine portion. Similar to the serpentine design, the fishbone design has a primary portion running throughout the optical backplane. The fishbone design also can include individual branches extending outward from the backbone portion to make individual connections with the optical backplane connectors.
As was the case with the xe2x80x9cpatch cordxe2x80x9d design, both the serpentine and the fishbone designs have disadvantages. One such disadvantage is that manufacturing a single fabric inter-connector which is capable of making the large number of interconnections necessary within an optical backplane can be difficult. A single flaw within the fabric inter-connector can render the entire piece unusable. Such demanding standards in manufacturability make the fabrication of single fabric inter-connector designs very difficult and costly. Oftentimes, the high performance of an optical backplane does not justify the high cost involved in fabricating the single serpentine or fishbone style fabric inter-connectors.
Another disadvantage of single fabric inter-connector designs is the inability of serpentine or fishbone designs to accommodate optical fibers having large bend radii. By design, single fabric inter-connectors are typically configured to pass in close proximity to optical backplane connectors. Due to the limited size of most optical backplanes, the fabric may be required to make tight bends to properly fit within the optical backplane. Additionally, each of the branches extending from the primary portion of the single fabric inter-connectors also may have to make tight bends to engage particular optical backplane connectors. In contrast, the fibers disposed throughout the optical fabric cannot bend beyond a predetermined bend radius without damaging the fiber or compromising its optical properties. Consequently, the degree to which a fabric inter-connector can be forced into a particular serpentine or fishbone shape, to a large extent, depends upon the bend radii of the optical fibers disposed therein, and not on the shape needed for interconnecting optical backplane connectors.
The invention disclosed herein provides an improved optical backplane assembly and a method of configuring the optical backplane assembly in accordance with the inventive arrangements disclosed herein. In particular, the invention provides an optical backplane assembly which incorporates a plurality of fiber-optic fabric inter-connectors (fabric inter-connectors), each of which can communicatively link selected optical backplane connectors. Rather than relying upon a single, complex optical fabric design or a series of individual patch cord type optical fabrics, the present invention provides for an optical backplane having several fabric inter-connectors, each having a plurality of legs.
The present invention provides for an optical backplane assembly as well as a method of configuring the optical backplane assembly wherein the fabric inter-connectors can be configured to cooperatively stack and at least partially overlap with one another. Further, the individual fabric inter-connectors can be configured in accordance with the physical dimensions of the optical backplane assembly as well as the physical location of the optical backplane connectors disposed therein. Each individual fabric inter-connector can include a visual identifier distinguishing it from the other optical fabrics within the optical backplane. In consequence, the present invention provides a high degree of manufacturability and an inexpensive design that can meet or exceed the strict size limitations typically imposed upon optical backplanes. Moreover, the present invention can be more easily serviced whether the unit is in production or has been placed in the field.
One aspect of the present invention can include an optical backplane assembly and method of configuring the optical backplane assembly. The optical backplane assembly can be configured to include a structural member for supporting a plurality of optical backplane connectors and a plurality of fabric inter-connectors. Each one of the plurality of fabric inter-connectors can include a substantially flat body portion and a plurality of legs extending outward from the body portion. In one embodiment of the present invention, each of the fabric inter-connectors can include at least three legs. Each of the legs includes an optical fiber bundle disposed therein and an optical fiber connector for cooperatively engaging selected ones of the plurality of optical backplane connectors. Notably, the body portions of the plurality of fabric inter-connectors can be stacked so as to at least partially overlap one another.
In another aspect of the invention, and in accordance with various embodiments of the inventive method and apparatus disclosed herein, each leg can be configured to include a service loop portion. In consequence, defective optical fiber connectors can be removed and replaced on any leg without having to replace the entire fabric inter-connector. The service loops allow for the excess fabric to re-terminate the optical fiber connectors. Additionally, the fabric inter-connectors can be marked with a unique visual identifier which can appear throughout the body portion and the legs. For example, the unique visual identifier can be a color.
In another aspect of the invention, each of the body portions can be configured to share a common co-equal dimension such as a length or a width. The legs further can be selectively configured to have at least a minimum length so as to accommodate a predetermined minimum bend radius for at least one optical fiber disposed therein.
The structural member can be configured to include a containment structure within which the body portions of the plurality of fabric inter-connectors can be exclusively positioned. Additional containment structures can be provided for securing at least one of the body portions of the plurality of fabric inter-connectors within a containment zone. The containment zone can be exclusive of the optical backplane connectors, whereby the body portions do not substantially obstruct the plurality of optical backplane connectors.
In yet another aspect of the invention, and in accordance with various embodiments of the inventive method and apparatus disclosed herein, the body portion of each one of the plurality of fabric inter-connectors can be configured with a predetermined shape based upon the physical dimensions of the optical backplane assembly and the physical placement of the optical backplane connectors disposed therein. The predetermined shapes can be configured for cooperatively stacking with one another. For example, the predetermined shape of each body portion can be selectively configured not to extend beyond a perimeter of an adjacent one of the body portions. Alternatively, each body portion can be selectively configured to fit within a perimeter of an adjacent one of the body portions so as to leave exposed at least a tab portion of the adjacent body portion.